The invention relates to an airbag module for motor vehicles, comprising a housing for an inflatable airbag and a gas generator.
Airbag modules of this kind serve to accommodate the airbag in the folded together state and to inflate it by means of the gas generator in the event of an accident. The airbag modules are installed in the vehicle as a unit. In this, conflicts can arise with other functional units of the motor vehicle which were previously located at the places where the airbag module is now to be provided in order to offer an ideal protection for the vehicle passenger. For example in drivers"" airbags which are to be accommodated in the central region of the steering wheel an ideal capability of functioning both of the airbag system and of the horn system of the vehicle must be ensured if the latter is to be likewise provided in the central region of the steering wheel. Furthermore, problems can arise if oscillations which arise during the operation of the vehicle are transmitted to the airbag module and the airbag module is integrated into the vehicle in such a manner that further tasks are assigned to it in addition to the protective function. Not only the driving comfort, but also additional functions of this kind can be impaired through oscillations of the airbag module.
The problem (object) of the invention is to create an airbag module of the initially named kind which is constructed as simply as possible, is not impaired by arising oscillations and can be used in particular as a drivers"" airbag which can be integrated into a steering wheel unit.
In accordance with the invention only the elastic and/or oscillation damping coupling member is required for coupling the gas generator to the housing. As a result of the coupling without securing means, no separate securing means such as for example screws or the like are required. Through this the attachment of the gas generator at the housing and thus the assembly of the airbag module is particularly simple.
The elastic and/or oscillation damping coupling member provides for a decoupling between the gas generator and the housing. Through this it is possible to subdivide the total mass of the airbag module substantially into the mass of the housing and of the airbag on the one hand and into the mass of the gas generator on the other hand. Through this the mass of the gas generator can fulfill an oscillation damping function in an advantageous manner. If the airbag module in accordance with the invention is integrated into a steering wheel unit, disturbing oscillations of the steering wheel can be avoided or reduced through suitable design of the coupling member. The respective masses and the respective type of coupling to the steering wheel system can be intentionally matched to additional functions which are to be transferred to the housing and/or to the gas generator in the installed state.
Through the coupling of the gas generator to the housing, the housing with the gas generator which is attached to it and thus the airbag module as a whole can be attached at a motor vehicle, for example at a steering wheel unit. Through the coupling member it is ensured that the gas generator and the housing can move independently of one another; i.e. the gas generator can execute oscillatory movements independently of the housing.
In a preferred embodiment of the invention the coupling member has a closed peripheral contour and is formed in particular in the shape of a ring. A coupling member of this kind enables a particularly simple attachment of the gas generator at the housing.
To connect the gas generator to the coupling member a particularly preferred embodiment of the invention proposes hanging in the gas generator into the coupling member.
In accordance with a particularly preferred embodiment the gas generator is connected to the coupling member in the manner of a bayonet lock. Through this a connection between the gas generator and the coupling member which is simple to manufacture and which is at the same time particularly secure is achieved.
The coupling member preferably has at least one in particular groove-like or slit-like recess at an inner side with which a holding section of the gas generator which projects preferably perpendicularly from an outer wall of the gas generator is in engagement.
To connect the coupling member to the housing it is provided in accordance with a further preferred exemplary embodiment of the invention that the housing, in particular a base plate, is pushed on onto the coupling member.
For this the coupling member preferably has at least one in particular circumferential and preferably groove-like or slit-like recess at an outer side with which a holding section of the housing is in engagement.
An edge region of the housing base which bounds a base opening which is provided for the gas generator preferably serves to connect the housing to the coupling member.
A particularly secure and nevertheless elastic and/or oscillation damping coupling between the gas generator and the housing is achieved in accordance with a further preferred embodiment of the invention in that sections of the gas generator and of the housing which are in engagement with the coupling member overlap each other in the radial direction.
The coupling member can be provided as a separate component or be formed on at the housing or moulded to the housing, in particular vulcanized on the housing, in particular a base plate of the housing.
A particularly preferred practical embodiment of the invention proposes providing the coupling member as a sealing between the gas generator and the housing. Through this the coupling member fulfills a plurality of functions at the same time in that it provides not only for an elastic and/or oscillation damping coupling of the gas generator to the housing, but also serves as a sealing. Through this it is possible in an advantageous manner to seal off the interior of the housing containing the inflatable airbag or of the airbag surrounding the gas generator respectively against the surroundings with the coupling member.
In accordance with a further preferred exemplary embodiment of the invention the coupling member is clamped in between a diffuser and a base plate of the housing, with the diffuser and the base plate preferably being screwed together. In this way the diffuser provides for a secure fixing of the coupling member and thus of the gas generator at the housing.
This fixing is of particular advantage in particular when damages, e.g. fissures, arise at the coupling member during the vehicle operation. The diffuser holds the coupling member and thus the gas generator in position, so that it is ensured that after the triggering of the gas generator the gas which is ejected from the latter reliably enters into the airbag to be inflated even if the coupling member is damaged or is torn in or torn through.
It is preferred for the diffuser to be formed as a protection against rotation for the coupling member.
In accordance with a further preferred embodiment of the invention it is provided that a diffuser surrounds the gas generator at least region-wise with spacing, with the intermediate space preferably forming a gas inlet chamber which is sealed off by the coupling member.
In this way the gas generator can execute oscillations within the diffuser uninfluenced by other components of the airbag module. In particular a contact between the oscillating gas generator and the airbag can be avoided through the diffuser.
The coupling by means of the coupling member is preferably designed in such a manner that the gas generator can be moved relative to the housing with a radial component which extends perpendicularly to a propagation direction of the airbag. The gas generator can thereby execute radial oscillations which extend perpendicularly to its longitudinal axis.
Further preferred embodiments of the invention are also set forth in the subordinate claims, the description and the drawings.